Sources of contaminated water, such as industrial wastewater, typically contain contaminants which are hazardous or potentially hazardous to the environment, as well as to the health of (human, animal, agricultural) living entities. Such contaminants may be in the form of volatile or/and semi-volatile compounds, for example, volatile organic compounds (VOCs) or/and semi-volatile organic compounds (SVOCs), as well as volatile or/and semi-volatile inorganic compounds.
In accordance with well established and implemented environmental regulations, industrial wastewater must be processed (via water treatment or purification techniques) so as to remove, or at least substantially decrease amounts of, hazardous contaminants contained therein, thereby, eliminating or at least mitigating hazards associated with the wastewater.
Removing volatile compounds from contaminated water sources, such as industrial wastewater or other contaminated aqueous streams, is widely and commonly done by using steam stripping processes and techniques. In steam stripping, externally generated steam, functioning as a stripping gas, and contaminated water are counter-currently fed into bottom and top portions, respectively, of a stripping column. The contaminated water is directly contacted (via interaction with large surface area provided by packing material supported upon trays) by the steam which volatizes and removes (strips away) volatile compounds from the contaminated water into a vapor phase. The resulting vapor phase of steam and volatile compounds exits the stripping column as exhaust and is further processed, for example, via condensation to provide a water phase and a volatile compound phase. The volatile compound phase is typically separated from the water phase and further processed, for example, via incineration (such as thermal oxidation) or recovered for other use. The resulting (mostly, but not entirely) stripped contaminated water, via batch mode steam stripping, is typically recycled and combined with additional contaminated water for further stripping cycles, or, via continuous mode steam stripping, is removed for further processing, ultimately leading to producing cleaner or purer, and environmentally friendly, forms of water.
The same applicant/assignee of the present disclosure developed water treatment and purification techniques involving various combinations of steam stripping and regenerative thermal oxidation (RTO) processes (e.g., direct thermal, flare, or thermo-catalytic, RTO processes). According to such techniques, following steam stripping contaminated water, the volatile compound phase (vapor phase of steam and volatile compounds) exiting the stripping column as exhaust is subjected to an RTO process, resulting in further removing volatile compounds originally present in the initial contaminated water. Exemplary teachings and practices of such water treatment and purification techniques are described in: PCT International Patent Application Publication No. WO 2008/026196; and U.S. Pat. Nos. 8,282,837; 7,722,775; and 7,455,781, all commonly assigned with the present application, the entire contents of which are incorporated in this application as if fully set forth.
According to an aspect of some embodiments of the present invention there is provided a method for processing contaminated water containing volatile or/and semi-volatile compounds, the method comprising: superheating the contaminated water, for forming superheated contaminated water having a temperature equal to or higher than a predetermined threshold temperature; flash evaporating the superheated contaminated water, for forming superheated contaminated steam; and thermally oxidizing the superheated contaminated steam, so as to thermally oxidize the volatile or/and semi-volatile compounds contained therein, and form thermal oxidation gas/vapor products.
According to some embodiments of the invention, the superheating, the predetermined threshold temperature is equal to or higher than a temperature selected from the group consisting of 103° C., 104° C., 105° C., and 110° C.
According to some embodiments of the invention, the superheating, the predetermined threshold temperature is maintained with a predetermined temperature range of about ten degrees, or of about two degrees.
According to some embodiments of the invention, the superheating is performed so that the superheated contaminated water remains at the predetermined threshold temperature when initiating the flash evaporating process.
According to some embodiments of the invention, the method further comprises controlling integrated operation of, and processing data-information associated with, the superheating, the flash evaporating, and the thermally oxidizing, via a process control/data-information processing unit.
According to some embodiments of the invention, the flash evaporating includes controlling the temperature and rate of evaporation of the superheated contaminated water, so as to control amount and concentration of the superheated contaminated water, and of the superheated contaminated steam subjected to the thermally oxidizing process, via a process control/data-information processing unit.
According to some embodiments of the invention, the method further comprises recycling heat from the thermal oxidation gas/vapor products to the superheating, thereby providing heat for performing the superheating.
According to some embodiments of the invention, the method further comprises controlling integrated operation of, and processing data-information associated with, the superheating, the flash evaporating, the thermally oxidizing, and the recycling heat.
According to some embodiments of the invention, the superheating is spatially and temporally directly, and sequentially immediately, operatively connected to, and followed by, the flash evaporating.
According to some embodiments of the invention, the flash evaporating is spatially and temporally directly, and sequentially immediately, operatively connected to, and followed by, the thermally oxidizing.
According to some embodiments of the invention, the method further comprises recycling heat from the thermal oxidation gas/vapor products to the superheating, wherein the recycling heat is spatially and temporally directly, and sequentially immediately, operatively connected to, and followed by, the superheating.
According to an aspect of some embodiments of the present invention there is provided a system for processing contaminated water containing volatile or/and semi-volatile compounds, the system comprising: a superheating unit that superheats the contaminated water forms superheated contaminated water having a temperature equal to or higher than a predetermined threshold temperature; a flash evaporation unit, operatively connected to the superheating unit, that flash evaporates the superheated contaminated water and forms superheated contaminated steam; and a thermal oxidation unit, operatively connected to the flash evaporation unit, that thermally oxidizes the superheated contaminated steam, so as to thermally oxidize the volatile or/and semi-volatile compounds contained therein, and form thermal oxidation gas/vapor products.
According to some embodiments of the invention, the superheating unit is spatially and temporally directly, and sequentially immediately, operatively connected to, and followed by, the flash evaporation unit.
According to some embodiments of the invention, the flash evaporation unit is spatially and temporally directly, and sequentially immediately, operatively connected to, and followed by, the thermal oxidation unit.
According to some embodiments of the invention, the system further comprises a heat recycling unit operatively connected to the thermal oxidation unit and the superheating unit, that recycles heat from the thermal oxidation gas/vapor products to the superheating unit, wherein the heat recycling unit is spatially and temporally directly, and sequentially immediately, operatively connected to, and followed by, the superheating unit.
According to some embodiments of the invention, the superheating unit maintains the predetermined threshold temperature equal to or higher than a temperature selected from the group consisting of 103° C., 104° C., 105° C., and 110° C.
According to some embodiments of the invention, the system further comprises a process control/data-information processing unit, operatively connected to, and controlling integrated operation of and processing data-information associated with, the superheating unit, the flash evaporation unit, and the thermal oxidation unit.
According to some embodiments of the invention, the superheating unit is controlled by the process control/data-information processing unit, so that the superheating unit maintains the predetermined threshold temperature of the superheated contaminated water when the superheated contaminated water enters the flash evaporation unit.
According to some embodiments of the invention, the flash evaporation unit is controlled by the process control/data-information processing unit, by controlling the temperature and rate of evaporation of the superheated contaminated water inside the flash evaporation unit, so as to control amount and concentration of the superheated contaminated water, and of the superheated contaminated steam entering the thermal oxidation unit.
According to some embodiments of the invention, the system further comprises a heat recycling unit, operatively connected to the thermal oxidation unit and the superheating unit, that recycles heat from the thermal oxidation gas/vapor products to the superheating unit.
According to some embodiments of the invention, the system further comprises a process control/data-information processing unit, operatively connected to, and, controlling integrated operation of and processing data-information associated with, the superheating unit, the flash evaporation unit, the thermal oxidation unit, and the heat recycling unit.
All technical or/and scientific words, terms, or/and phrases, used herein have the same or similar meaning as commonly understood by one of ordinary skill in the art to which the invention pertains, unless otherwise specifically defined or stated herein. Methods, materials, and examples described herein are illustrative only and are not intended to be necessarily limiting. Although methods or/and materials equivalent or similar to those described herein can be used in practicing or/and testing embodiments of the invention, exemplary methods or/and materials are described below. In case of conflict, the patent specification, including definitions, will control.
Implementation of some embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of some embodiments of the invention, several selected tasks could be implemented by hardware, by software, by firmware, or a combination thereof, using an operating system.
For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip, as a circuit, or a combination thereof. As software, selected tasks of some embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks of exemplary embodiments of the method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions or/and data. Alternatively or additionally, optionally, the data processor includes a non-volatile storage, for example, a magnetic hard-disk or/and removable media, for storing instructions or/and data. Optionally, a network connection is provided as well. Optionally, a display or/and a user input device such as a keyboard or mouse is provided as well.